Caps can be made either of metal or plastic, wherein the latter are normally produced in an injection molding machine, ejected, cooled in a bulk container during subsequent transport, oriented upon leaving the bulk container and placed in gapless lines and subsequently separated and cut in or before a cutting machine to produce a tamper-proof cap, or are further processed with another machine. Subsequently the screw caps can be transported to filling stations and there be screwed onto filled containers. Before and/or after the cutting machine, the screw caps pass through a quality control, with specific consideration of color errors, incomplete injections, holes, burrs, injection points, the presence and the quality of gas barrier layers or other such attributes, whereby faulty screw caps are sorted out. Such in-line setups have since attained product-related processing speeds of 3,500 to 4,000 products per minute or more. Similar procedural steps with similar processing speeds are required for metal caps.
It is therefore particularly important to provide the individual work stations or handling stations continuously with caps, specifically screw caps, as well as to allow for corresponding interim storage. In this continuous supply line it is particularly important that the already-oriented objects not be changed in their orientation when placed into interim storage, so that the machines being supplied with objects can operate continuously and maintain high processing speeds. Furthermore it is important to introduce the oriented objects to the machines themselves, or to conveyor systems to the machines, with a corresponding dynamic pressure, so that they are constantly and at all times able to accept an object or have an object delivered to them, so that no uncapped containers result.
In general, the invention pertains to an interim storage system for objects that have already been oriented. The interim storage system in accordance with this invention additionally includes an object inlet, a rotating turntable, a fixed spiral-shaped object path, and an object outlet, wherein either the object inlet or the object outlet is aligned with the origin of the spiral, while the other is aligned with the end of the spiral. More specifically, the invention pertains to an interim storage system for in-line conveyed and oriented screw caps, particularly those made of plastic, with the following characteristics.
A rotating buffer storage system is known from WO 2008/030 937 A2, in which a driven turntable includes a spiral-shaped barrier that is connected to it, and thus rotating with it, which defines a product path from the outer area of the turntable to the inner area, wherein a fixed bridge spans the turntable, from which fingers protrude into the product path, for example to measure the speed of the objects. The rotation speed of the turntable is controlled by a computer. After complete filling, the buffer storage system is emptied, meaning that it works in batch mode and is therefore not ideal for the application covered by this invention.
U.S. Pat. No. 5,234,098 A demonstrates a turntable with a non-rotating but vibrating spiral path which is continuously supplied with bulk frozen food items such as peas, wherein the individual peas are separated out of frozen groups upon passing through the vibrating spiral path with increasing distance from one another, so that the peas leave the turntable in a single row. Understandably, the orientation of the peas in this process is unimportant.